Add custom timeouts for ConceptEV and OCM clients

### 📝 Description of the feature

We need to add timeout values to the httpx clients that are configurable.
We need to create better error messages when it hits a timeout.

### 💡 Steps for implementing the feature

_No response_

### 🔗 Useful links and references

_No response_

Start by locating the ConceptEV and OCM httpx clients referenced in the issue and inspect how they are constructed and how timeout exceptions are currently surfaced. Define configurable timeout values for both clients and clearer timeout errors, then verify the client behavior with the project's existing tests.

Written by the indexing model from the issue text.